KR20210138746A - Method for producing sulfide-based inorganic solid electrolyte material - Google Patents

Abstract

A manufacturing method for manufacturing a sulfide-based inorganic solid electrolyte material containing Li, P and S as constituent elements, comprising: a preparation step of preparing a raw inorganic composition (A) containing at least lithium sulfide, phosphorus sulfide and a crystal nucleating agent; and a vitrification step of vitrifying the raw inorganic composition (A) by mechanically treating the raw inorganic composition (A).

Description

Method for producing sulfide-based inorganic solid electrolyte material

The present invention relates to a method for producing a sulfide-based inorganic solid electrolyte material.

Lithium ion batteries are generally used as power sources for small portable devices such as cellular phones and notebook computers. In addition, lithium ion batteries are beginning to be used as power sources for electric vehicles and power storage in addition to small portable devices in recent years.

An electrolyte containing a combustible organic solvent is used in lithium ion batteries currently on the market. On the other hand, a lithium ion battery (hereinafter also referred to as an all-solid lithium ion battery) in which an electrolyte is replaced with a solid electrolyte and the battery is solidified does not use a flammable organic solvent in the battery, so the safety device can be simplified. , is considered to be excellent in manufacturing cost and productivity. As a solid electrolyte material used for such a solid electrolyte, for example, a sulfide-based inorganic solid electrolyte material is known.

For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2016-27545), it has a peak at the position of 2θ=29.86°±1.00° in X-ray diffraction measurement using CuKα ray, and Li _2y+3 PS ₄ A sulfide-based solid electrolyte material having a composition of (0.1≤y≤0.175) is described.

Japanese Patent Laid-Open No. 2016-27545

A sulfide-based inorganic solid electrolyte material as described in Patent Document 1 is a raw material inorganic composition containing two or more kinds of inorganic compounds, which are generally raw materials for an inorganic solid electrolyte material, mechanically using a method such as a mechanical milling method. It is obtained through the process of vitrification by processing.

However, according to the examination of the present inventors, it became clear that the process of vitrifying a raw material inorganic composition by mechanical treatment takes a very long time, and productivity is bad. That is, the method for producing a sulfide-based inorganic solid electrolyte material including a step of vitrifying the raw inorganic composition by mechanical treatment as described above is not suitable for industrial production.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a sulfide-based inorganic solid electrolyte material capable of shortening the production time by allowing the vitrification step to be performed in a shorter time.

MEANS TO SOLVE THE PROBLEM In order to achieve the said subject, the present inventors repeated earnest examination. As a result, it was discovered that the vitrification step of the inorganic composition can be shortened by carrying out the vitrification step after containing the crystal nucleating agent with respect to the raw inorganic composition before the vitrification step, and the present invention has been completed.

According to the present invention,

As a manufacturing method for manufacturing a sulfide-based inorganic solid electrolyte material containing Li, P and S as constituent elements,

A preparation step of preparing a raw material inorganic composition (A) containing at least lithium sulfide, phosphorus sulfide, and a crystal nucleating agent;

A vitrification process of vitrifying the raw inorganic composition (A) by mechanically treating the raw inorganic composition (A)

There is provided a method for producing a sulfide-based inorganic solid electrolyte material comprising a.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the sulfide type inorganic solid electrolyte material which can carry out the vitrification process in a shorter time and can shorten the manufacturing time can be provided.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described. In addition, unless otherwise stated, "A to B" in a numerical range represents A or more and B or less.

First, the manufacturing method of the sulfide-type inorganic solid electrolyte material of this embodiment is demonstrated.

The method for producing a sulfide-based inorganic solid electrolyte material of the present embodiment is a production method for producing a sulfide-based inorganic solid electrolyte material containing Li, P and S as constituent elements, comprising at least lithium sulfide, phosphorus sulfide and a crystal nucleating agent. It includes a preparation step of preparing the raw inorganic composition (A) containing the raw material inorganic composition (A), and a vitrification process of vitrifying the raw material inorganic composition (A) by mechanically treating the raw material inorganic composition (A).

According to the manufacturing method of the sulfide type inorganic solid electrolyte material of this embodiment, compared with the conventional manufacturing method, the process of vitrifying an inorganic composition can be shortened, As a result, manufacture of the sulfide type inorganic solid electrolyte material of this embodiment It is possible to shorten the time.

The sulfide-based inorganic solid electrolyte material obtained by the method for producing the sulfide-based inorganic solid electrolyte material of the present embodiment contains Li, P and S as constituent elements.

In addition, from the viewpoint of further improving lithium ion conductivity, electrochemical stability, stability in water or air, handling properties, and the like, the sulfide-based inorganic solid electrolyte material of the present embodiment contains the P in the sulfide-based inorganic solid electrolyte material. The molar ratio Li/P of the content of Li to the content of It is 4.2 or less, More preferably, it is 3.3 or more and 4.0 or less, Especially preferably, it is 3.3 or more and 3.8 or less.

Further, the molar ratio S/P of the content of S to the content of P is preferably 1.0 or more and 10.0 or less, more preferably 2.0 or more and 6.0 or less, still more preferably 3.0 or more and 5.0 or less, and still more preferably Preferably, it is 3.5 or more and 4.5 or less, Especially preferably, it is 3.8 or more and 4.2 or less.

Here, the contents of Li, P, and S in the sulfide-based inorganic solid electrolyte material of the present embodiment can be determined by, for example, ICP emission spectroscopy or X-ray analysis.

The sulfide-based inorganic solid electrolyte material of the present embodiment can be used for any application requiring lithium ion conductivity. Especially, it is preferable that the sulfide-type inorganic solid electrolyte material of this embodiment is used for a lithium ion battery. More specifically, it is used for a positive electrode active material layer, a negative electrode active material layer, an electrolyte layer, etc. in a lithium ion battery. In addition, the sulfide-based inorganic solid electrolyte material of the present embodiment is suitably used for a positive electrode active material layer, a negative electrode active material layer, a solid electrolyte layer, etc. constituting an all-solid lithium ion battery, and a solid electrolyte layer constituting an all-solid lithium ion battery. It is particularly suitable for use in

As an example of the all-solid-state lithium ion battery to which the sulfide-based inorganic solid electrolyte material of the present embodiment is applied, a positive electrode, a solid electrolyte layer, and a negative electrode are stacked in this order.

Each process will be described in detail below.

(Preparation process)

First, the raw material inorganic composition (A) containing at least lithium sulfide, phosphorus sulfide, and a crystal nucleating agent is prepared. The raw material inorganic composition (A) can be obtained, for example, by mixing the respective raw materials in a predetermined molar ratio so that the target sulfide-based inorganic solid electrolyte material has a desired composition ratio.

Here, the mixing ratio of each raw material in the raw material inorganic composition (A) is adjusted so that the obtained sulfide-based inorganic solid electrolyte material has a desired composition ratio.

The method of mixing each raw material is not particularly limited as long as it is a mixing method capable of uniformly mixing each raw material, but for example, a ball mill, bead mill, vibration mill, blow mill, mixer (pug mixer, ribbon mixer, tumbler mixer) , drum mixer, V-type mixer, etc.), a kneader, a twin-screw kneader, an airflow grinder, etc. can be used for mixing.

Mixing conditions such as agitation speed, treatment time, temperature, reaction pressure, and gravitational acceleration applied to the mixture when each raw material is mixed can be appropriately determined according to the amount of processing of the mixture.

It does not specifically limit as lithium sulfide used as a raw material, Commercially available lithium sulfide may be used, For example, lithium sulfide obtained by reaction of lithium hydroxide and hydrogen sulfide may be used. It is preferable to use lithium sulfide with few impurities from the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and from the viewpoint of suppressing side reactions.

Here, in this embodiment, lithium polysulfide is also contained in lithium sulfide. _{Li 2} S is preferable as lithium sulfide.

Is not particularly limited as long as the sulphide used as a starting material, a commercially available sulfide can be used (for _{example, P 2 S 5, P 4} S 3, P 4 S 7, P 4 S 5 , etc.). From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and suppressing side reactions, it is preferable to use phosphorus sulfide with few impurities. As phosphorus sulfide, P ₂ S ₅ is preferable.

As a crystal nucleating agent used as a raw material, an inorganic solid electrolyte material can be used, for example.

Although it does not specifically limit as said inorganic solid electrolyte material, A sulfide type inorganic solid electrolyte material, oxide type inorganic solid electrolyte material, other lithium type inorganic solid electrolyte material, etc. are mentioned. Among these, from the viewpoint of further improving the ion conductivity of the obtained sulfide-based inorganic solid electrolyte material, a sulfide-based inorganic solid electrolyte material is preferable as a crystal nucleating agent used as a raw material, and contains Li, P and S as constituent elements. A sulfide-based inorganic solid electrolyte material is more preferable.

Moreover, although it does not specifically limit as said inorganic solid electrolyte material, For example, what is used for the solid electrolyte layer which comprises an all-solid-type lithium ion battery is mentioned.

Examples of the sulfide-based inorganic solid electrolyte material include Li ₂ S-P ₂ S ₅ material, Li ₂ S-SiS ₂ material, Li ₂ S-GeS ₂ material, Li ₂ S-Al ₂ S ₃ material, Li ₂ S-SiS ₂ -Li ₃ PO ₄ material, Li ₂ S-P ₂ S ₅ -GeS ₂ material, Li ₂ S-Li ₂ O-P ₂ S ₅ -SiS ₂ material, Li ₂ S-GeS ₂ -P ₂ S ₅ -SiS ₂ material, Li ₂ S-SnS ₂ -P ₂ S ₅ -SiS ₂ material, Li ₂ S-P ₂ S ₅ -Li ₃ N material, Li ₂ S _2+X -P ₄ S ₃ material, Li _2, and the like _{s-P 2 s 5 -P 4} s 3 material.

_{Among these, Li 2} S-P ₂ S ₅ material is preferable from the viewpoint of excellent lithium ion conductivity and stability in not causing decomposition or the like in a wide voltage range. Here, for example, the Li ₂ S-P ₂ S ₅ material is an inorganic obtained by chemically reacting an inorganic composition containing at least Li ₂ S (lithium sulfide) and P ₂ S _{5 (phosphorus sulfide) by mechanical treatment.} means material.

Here, in this embodiment, lithium polysulfide is also contained in lithium sulfide.

Examples of the oxide-based inorganic solid electrolyte material include NASICON types such as _{LiTi 2} (PO ₄ ) ₃ , LiZr ₂ (PO ₄ ) ₃ , LiGe ₂ (PO ₄ ) _{3 , (La 0.5+x} Li _0.5-3x ) TiO _3, and the like of the perovskite _{type, Li 2 O-P 2 O} 5 _{ingredients, Li 2 O-P 2 O} 5 -Li 3 N materials.

As other lithium-based inorganic solid electrolyte materials, for example, LiPON, LiNbO ₃ , LiTaO ₃ , Li ₃ PO ₄ , LiPO _4-x N _x (x is 0<x≤1), LiN, LiI, LISICON, etc. can be heard

In addition, glass ceramics obtained by precipitating crystals of these inorganic solid electrolytes can also be used as the inorganic solid electrolyte material.

The sulfide-based inorganic solid electrolyte material used as the crystal nucleating agent preferably has lithium ion conductivity and contains Li, P and S as constituent elements.

In addition, the sulfide-based inorganic solid electrolyte material used as the crystal nucleating agent is from the viewpoint of further improving the lithium ion conductivity, electrochemical stability, stability in water and air, handling properties, etc. of the resulting sulfide-based inorganic solid electrolyte material, The molar ratio Li/P of the content of Li to the content of P in the sulfide-based inorganic solid electrolyte material is preferably 1.0 or more and 10.0 or less, more preferably 1.0 or more and 5.0 or less, still more preferably 2.0 or more and 4.5 or less. and even more preferably 3.0 or more and 4.2 or less, still more preferably 3.3 or more and 4.0 or less, and particularly preferably 3.3 or more and 3.8 or less.

Further, the molar ratio S/P of the content of S to the content of P is preferably 1.0 or more and 10.0 or less, more preferably 2.0 or more and 6.0 or less, still more preferably 3.0 or more and 5.0 or less, and still more preferably Preferably, it is 3.5 or more and 4.5 or less, Especially preferably, it is 3.8 or more and 4.2 or less.

Here, the contents of Li, P, and S in the sulfide-based inorganic solid electrolyte material used as the crystal nucleating agent can be determined by, for example, ICP emission spectroscopy or X-ray photoelectron spectroscopy.

As a shape of the inorganic solid electrolyte material used as a crystal nucleating agent, a particulate form is mentioned, for example. The particulate inorganic solid electrolyte material is not particularly limited, but the average particle diameter (d ₅₀ ) in the weight-based particle size distribution by laser diffraction scattering particle size distribution measurement method is preferably 1 µm or more and 50 µm or less, and more preferably It is 2 micrometers or more and 40 micrometers or less, More preferably, they are 3 micrometers or more and 35 micrometers or less.

The content of the crystal nucleating agent contained in the raw inorganic composition (A) is preferably 5 mass% or more when the total amount of the raw inorganic composition (A) is 100 mass% from the viewpoint of further shortening the vitrification process; More preferably, it is 10 mass % or more, More preferably, it is 15 mass % or more, More preferably, it is 20 mass % or more, Especially preferably, it is 25 mass % or more. The upper limit of the content of the crystal nucleating agent contained in the raw inorganic composition (A) is preferably 60 mass% or less from the viewpoint of reducing the amount of the crystal nucleating agent used and increasing the production amount of the obtained sulfide-based inorganic solid electrolyte material, more Preferably it is 50 mass % or less, More preferably, it is 45 mass % or less, Especially preferably, it is 35 mass % or less.

You may further use lithium nitride as a raw material. Here, since nitrogen in lithium nitride _{is discharged into the system as N 2} , by using lithium nitride as an inorganic compound as a raw material, with respect to a sulfide-based inorganic solid electrolyte material containing Li, P, and S as constituent elements, only the Li composition It becomes possible to increase

Is not particularly limited as lithium nitride in the present embodiment, the lithium nitride on the market and may be used (for example, Li ₃ N and the like), for example, metal lithium (for example, Li day) and nitrogen gas You may use lithium nitride obtained by reaction. It is preferable to use lithium nitride with few impurities from the viewpoint of obtaining a high-purity solid electrolyte material and from the viewpoint of suppressing side reactions.

(Vitrification process)

Subsequently, the raw inorganic composition (A) is subjected to mechanical treatment to vitrify the raw inorganic composition (A). That is, lithium sulfide and phosphorus sulfide, which are raw materials, are vitrified while chemically reacting to obtain a glassy sulfide-based inorganic solid electrolyte material.

Here, the mechanical treatment can be made vitrified while chemically reacting by mechanically colliding two or more types of inorganic compounds, for example, mechanochemical treatment or the like.

Further, in the vitrification step, from the viewpoint of easily realizing an environment in which moisture and oxygen are removed at a high level, the mechanical treatment is preferably dry, and more preferably a dry mechanochemical treatment.

When the mechanochemical treatment is used, each raw material can be mixed while pulverizing it into fine particles, so that the contact area of each raw material can be increased. Thereby, since the reaction of each raw material can be accelerated|stimulated, the sulfide type inorganic solid electrolyte material of this embodiment can be obtained more efficiently.

Here, the mechanochemical treatment is a method of vitrification while applying mechanical energy such as shear force, impact force or centrifugal force to the target composition. Examples of the device for vitrification by mechanochemical treatment include grinding and dispersing machines such as ball mills, bead mills, vibration mills, turbo mills, mechanofusions, disk mills, and roll mills; A rotating/blowing grinding device comprising a mechanism combining (shear stress) and hitting (compressive stress); high-pressure grinding rolls and the like. Among these, from a viewpoint of being able to generate|occur|produce very high impact energy efficiently, a ball mill and a bead mill are preferable, and a ball mill is especially preferable. In addition, from the viewpoint of excellent continuous productivity, a roll mill; a rotary/striking grinding device comprising a mechanism combining rotation (shear stress) and striking (compressive stress) typified by rock cutters, vibrating drills, and impact drivers; high-pressure grinding rolls etc. are preferable.

Further, the mechanochemical treatment is preferably performed in an inert atmosphere. Thereby, the reaction between the sulfide-based inorganic solid electrolyte material and water vapor, oxygen, or the like can be suppressed.

In addition, the said inert atmosphere means under a vacuum atmosphere or an inert gas atmosphere. In the inert atmosphere, the dew point is preferably -50°C or less, and more preferably -60°C or less in order to avoid contact with moisture. The said inert gas atmosphere means the atmosphere of inert gas, such as argon gas, helium gas, and nitrogen gas. In order to prevent mixing of impurities into a product, these inert gases are preferable as it is high purity. The method for introducing the inert gas into the mixed system is not particularly limited as long as the inside of the mixed system is filled with an inert gas atmosphere, and examples include a method of purging an inert gas and a method of continuously introducing an inert gas in a certain amount.

When the raw inorganic composition (A) is mechanically treated, mixing conditions such as rotation speed, treatment time, temperature, reaction pressure, and gravitational acceleration applied to the raw inorganic composition (A) depend on the type of raw inorganic composition (A) and the amount of treatment. can be appropriately determined according to In general, the faster the rotational speed, the faster the glass formation speed, and the longer the processing time, the higher the conversion rate to glass.

Normally, when X-ray diffraction analysis using CuKα ray as a ray source, if the diffraction peak derived from the raw material disappears or decreases, the raw material inorganic composition (A) is vitrified, and it is judged that the desired sulfide-based inorganic solid electrolyte material is obtained. can do.

Here, in the step of vitrifying the raw material inorganic composition (A), the lithium ion conductivity by the AC impedance method under the measurement conditions of 27.0° C., applied voltage 10 mV, and measurement frequency range of 0.1 Hz to 7 MHz is 0.5×10 ⁻⁴ It is preferable to perform a mechanical treatment until it becomes S*cm ^-1 or more, More preferably, it becomes 1.0x10 ^-4 S*cm ^{-1 or more.} Thereby, a sulfide-based inorganic solid electrolyte material having further excellent lithium ion conductivity can be obtained.

(crystallization process)

In the method for producing a sulfide-based inorganic solid electrolyte material of the present embodiment, from the viewpoint of further improving the lithium ion conductivity of the obtained sulfide-based inorganic solid electrolyte material, after the vitrification step, the obtained sulfide-based inorganic solid electrolyte material (hereinafter, vitrified) It is preferable to further perform a crystallization step of crystallizing at least a part of the inorganic composition (B) by heating the sulfide-based inorganic solid electrolyte material in the free state after the step (also called the inorganic composition (B)). By heating the obtained inorganic composition (B), at least a part of the inorganic composition (B) can be crystallized to obtain a sulfide-based inorganic solid electrolyte material in a glass-ceramics state (also referred to as crystallized glass). In this way, for example, a sulfide-based inorganic solid electrolyte material having further excellent lithium ion conductivity can be obtained.

That is, the sulfide-based inorganic solid electrolyte material of the present embodiment is preferably in a glass-ceramics state (crystallized glass state) from the viewpoint of excellent lithium ion conductivity.

The temperature at which the inorganic composition (B) is heated is not particularly limited as long as it is a temperature at which crystallization can sufficiently proceed. For example, from the viewpoint of effectively advancing crystallization while suppressing thermal decomposition of the inorganic composition (B), 220 It is preferably in the range of ℃ or more and 500 °C or less, preferably in the range of 250 °C or more and 400 °C or less, more preferably in the range of 260 °C or more and 350 °C or less, more preferably in the range of 270 °C or more and 350 °C or less desirable.

The heating time of the inorganic composition (B) is not particularly limited as long as it is the time for which the desired sulfide-based inorganic solid electrolyte material in the glass-ceramics state is obtained. For example, it is within the range of 1 minute or more and 24 hours or less, preferably is in the range of 0.5 hours or more and 8 hours or less, and more preferably in the range of 1 hour or more and 3 hours or less. Although the heating method is not specifically limited, For example, the method of using a calcination furnace is mentioned. In addition, conditions, such as temperature and time at the time of such heating, can be suitably adjusted in order to make the characteristic of a sulfide type inorganic solid electrolyte material optimal.

In addition, it is preferable to perform heating of an inorganic composition (B) in an inert gas atmosphere, for example. Thereby, deterioration (for example, oxidation) of the inorganic composition (B) can be prevented.

As an inert gas at the time of heating an inorganic composition (B), argon gas, helium gas, nitrogen gas, etc. are mentioned, for example. These inert gases are preferably of high purity in order to prevent mixing of impurities into the product. Further, in order to avoid contact with moisture, the dew point is preferably -50°C or less, and particularly preferably -60°C or less. The method for introducing the inert gas into the mixed system is not particularly limited as long as the inside of the mixed system is filled with an inert gas atmosphere, and examples include a method of purging an inert gas and a method of continuously introducing an inert gas in a certain amount.

(heating process)

In the method for producing a sulfide-based inorganic solid electrolyte material of the present embodiment, between the preparation step and the vitrification step, a step of heating the raw inorganic composition (A) prepared in the preparation step may be further performed.

That is, the above-mentioned vitrification step may be performed on the raw inorganic composition (A) subjected to the heat treatment.

By performing the heating step before the vitrification step, the step of vitrifying the raw inorganic composition (A) can be further shortened, and as a result, it is possible to further shorten the manufacturing time of the sulfide-based inorganic solid electrolyte material. The reason for this is not clear, but the following reasons are conjectured.

First, the inorganic composition in the free state is in a metastable state. On the other hand, the inorganic composition in the crystalline state is in a stable state. In addition, when an inorganic composition containing two or more kinds of inorganic compounds is heated, energy higher than the activation energy can be simply applied, so that an inorganic composition in a crystalline state, which is a low energy state, can be obtained in a short time along with the release of energy. And, since the free energy of a stable state and the free energy of a metastable state are close, it can be made into the free state of a metastable state from a stable state with a smaller energy.

For the above reasons, by performing a step of heating the raw inorganic composition (A) before the step of vitrifying the raw inorganic composition (A), and bringing the raw inorganic composition (A) into a stable crystalline state in advance, a smaller energy It can be made into a metastable glassy state, and it is thought that the process of vitrification of a raw material inorganic composition (A) can be shortened significantly.

The temperature at the time of heating the raw inorganic composition (A) is not particularly limited, and can be appropriately set depending on the sulfide-based inorganic solid electrolyte material to be produced.

For example, the heating temperature is preferably in the range of 200°C or more and 400°C or less, and more preferably 220°C or more and 300°C or less.

The time for heating the raw inorganic composition (A) is not particularly limited, but is, for example, within the range of 1 minute or more and 24 hours or less, and preferably 0.1 hour or more and 10 hours or less. Although the heating method is not specifically limited, For example, the method of using a calcination furnace is mentioned. In addition, conditions, such as temperature and time at the time of such heating, can be suitably adjusted in order to make the characteristic of the sulfide-type inorganic solid electrolyte material of this embodiment optimal.

In addition, whether or not the raw inorganic composition (A) has crystallized can be judged by whether or not a new crystal peak is generated in a spectrum obtained by, for example, X-ray diffraction using CuKα ray as a ray source.

(Process of crushing, classifying, or assembling)

In the method for producing the sulfide-based inorganic solid electrolyte material of the present embodiment, if necessary, a step of pulverizing, classifying, or granulating the obtained sulfide-based inorganic solid electrolyte material may be further performed. For example, it is possible to obtain a sulfide-based inorganic solid electrolyte material having a desired particle size by pulverizing it into fine particles and then adjusting the particle size by classification operation or granulation operation. The grinding method is not particularly limited, and known grinding methods such as mixer, airflow grinding, mortar, rotary mill, and coffee mill can be used. In addition, it does not specifically limit as said classification method, Well-known methods, such as a sieve, can be used.

These pulverization or classification are preferably performed in an inert gas atmosphere or in a vacuum atmosphere from the viewpoint of preventing contact with moisture in the air.

In order to obtain the sulfide-based inorganic solid electrolyte material of the present embodiment, it is important to appropriately adjust the respective steps. However, the method for producing the sulfide-based inorganic solid electrolyte material of the present embodiment is not limited to the above method, and the sulfide-based inorganic solid electrolyte material of the present embodiment can be obtained by appropriately adjusting various conditions.

As mentioned above, although embodiment of this invention was described, these are examples of this invention, and it is also possible to employ|adopt various structures other than the above.

In addition, this invention is not limited to the above-mentioned embodiment, The deformation|transformation, improvement, etc. within the range which can achieve the objective of this invention are included in this invention.

Example

The present invention will be described below by way of Examples and Comparative Examples, but the present invention is not limited thereto.

<Evaluation method>

First, the evaluation methods in the following Examples and Comparative Examples will be described.

(1) Measurement of lithium ion conductivity

For the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples, lithium ion conductivity was measured by an alternating current impedance method.

For the measurement of lithium ion conductivity, the Biologic company make, potentiostat/galvanostat SP-300 was used. The size of the sample was 9.5 mm in diameter, 1.2 to 2.0 mm in thickness, and the measurement conditions were an applied voltage of 10 mV, a measurement temperature of 27.0° C., a measurement frequency range of 0.1 Hz to 7 MHz, and the electrode was made of Li foil.

Here, as a sample for measuring lithium ion conductivity, using a press device, 150 mg of the powdery sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples was pressed at 270 MPa for 10 minutes with a diameter of 9.5 mm and a thickness of 1.2 to 2.0. A sulfide-based inorganic solid electrolyte material having a plate shape of mm was used.

<Example 1>

(1) Preparation of sulfide-based inorganic solid electrolyte material 1 for crystal nucleating agent

A sulfide-based inorganic solid electrolyte material 1 for a crystal nucleating agent was produced in the following procedure.

Li ₂ S (manufactured by Furukawa Kikai Kinzoku Co., Ltd., purity of 99.9%) and P ₂ S ₅ (manufactured by Kanto Chemical _{Co., Ltd.) and Li 3} N (manufactured by Furukawa Kikai Kinzoku Co., Ltd.) were used as the raw material.

Next, in an argon glove box, the Li ₂ S powder, the P ₂ S ₅ powder, and the Li ₃ N powder (Li ₂ S:P ₂ S ₅ : Li ₃ N=27:9:2 (molar ratio)) are precisely weighed. Thus, the entire powder was mixed in an agate mortar for 10 minutes.

Next, 1 g of the mixed powder is weighed, put together with 18 zirconia balls of φ10 mm in a zirconia pot (internal volume 45 mL), and pulverized and mixed with a planetary ball mill (rotation 800 rpm, revolution 400 rpm) for 30 hours, A glassy sulfide-based inorganic solid electrolyte material (Li ₁₀ P ₃ S ₁₂ ) was obtained.

Next, the glassy sulfide-based inorganic solid electrolyte material was annealed in argon at 290°C for 2 hours to obtain a _{glass-ceramic sulfide-based inorganic solid electrolyte material (Li 10} P ₃ S _{12 ).} Next, the obtained sulfide-based inorganic solid electrolyte material in the state of glass ceramics was pulverized and mixed with a planetary ball mill (rotation 800 rpm, revolution 400 rpm) for 30 hours, and revitrified to obtain a sulfide-based inorganic solid electrolyte material 1 for a crystal nucleating agent.

(2) Production of the target sulfide-based inorganic solid electrolyte material

A target sulfide-based inorganic solid electrolyte material was produced in the following procedure.

As the raw material, Li ₂ S (manufactured by Furukawa Kikai Kinzoku Co., Ltd., purity 99.9%), P ₂ S ₅ (manufactured by Kanto Chemical _{Co., Ltd.) and Li 3} N (manufactured by Furukawa Kikai Kinzoku Co., Ltd.) were used.

Next, in an argon glove box, the Li ₂ S powder, the P ₂ S ₅ powder, and the Li ₃ N powder (Li ₂ S:P ₂ S ₅ : Li ₃ N=27:9:2 (molar ratio)) are precisely weighed. Then, these raw powders were precisely weighed so that the sulfide-based inorganic spherical electrolyte material 1 for crystal nucleating agent had the content shown in Table 1, and the entire powder was mixed in an agate mortar for 10 minutes.

Next, 1 g of the mixed powder (the raw material inorganic composition (A)) was weighed, put together with 18 zirconia balls of φ10 mm in a zirconia pot (internal volume 45 mL), and a planetary ball mill (rotation 800 rpm, revolution 400 rpm) ) was pulverized and mixed (mechanochemical treatment) for 3 hours to obtain a _{glassy sulfide-based inorganic solid electrolyte material (Li 10} P ₃ S _{12 ).}

Next, the glassy sulfide-based inorganic solid electrolyte material was annealed in argon at 290°C for 2 hours to obtain a _{glass-ceramic sulfide-based inorganic solid electrolyte material (Li 10} P ₃ S _{12 ).}

The lithium ion conductivity was measured for each of the obtained sulfide-based inorganic solid electrolyte material in a glassy state and a sulfide-based inorganic solid electrolyte material in a glass-ceramics state. The obtained results are shown in Table 1.

<Examples 2 to 4 and Comparative Example 1>

In the same manner as in Example 1, except that the content of the sulfide-based inorganic solid electrolyte material 1 for crystal nucleating agent was changed as shown in Table 1, the glassy sulfide-based inorganic solid electrolyte material and the glass-ceramics-based sulfide-based inorganic solid electrolyte material (Li ₁₀ P ₃ S ₁₂ ) were prepared, respectively, and lithium ion conductivity was measured for the obtained sulfide-based inorganic solid electrolyte material in a glass state and a sulfide-based inorganic solid electrolyte material in a glass-ceramic state. The obtained results are shown in Table 1.

<Examples 5-9>

In the same manner as in Example 2, except that the mechanochemical treatment time by the planetary ball mill was changed as shown in Table 1, the sulfide-based inorganic solid electrolyte material in the glass state and the sulfide-based inorganic solid electrolyte material in the glass ceramic state (Li ₁₀ P ₃ S ₁₂ ) was prepared, respectively, and the lithium ion conductivity was measured for the obtained glassy sulfide-based inorganic solid electrolyte material and glass ceramics-based sulfide-based inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Examples 10-11 and Comparative Examples 2-3>

(1) Preparation of sulfide-based inorganic solid electrolyte material 2 for crystal nucleating agent

A sulfide-based inorganic solid electrolyte material 2 for a crystal nucleating agent was prepared in the same manner as the sulfide-based inorganic solid electrolyte material 1 for a crystal nucleating agent except that the mixing ratio of each raw material was adjusted so that the composition was Li ₃ PS _{4 .}

(2) Production of the target sulfide-based inorganic solid electrolyte material

The mixing ratio of each raw material is adjusted so that the composition is Li ₃ PS ₄ , the mechanochemical treatment time by the planetary ball mill is changed as shown in Table 1, and the type and content of the sulfide-based inorganic solid electrolyte material for the crystal nucleating agent Except for changing as shown in Table 1, in the same manner as in Example 1, a glassy sulfide-based inorganic solid electrolyte material and a glass-ceramics-based sulfide-based inorganic solid electrolyte material (Li ₃ PS ₄ ) were prepared, respectively, and the obtained glassy state Lithium ion conductivity was measured for each of the sulfide-based inorganic solid electrolyte material and the sulfide-based inorganic solid electrolyte material in the glass ceramics state. The obtained results are shown in Table 1.

When comparing mechanochemical processing time and types of sulfide-based inorganic solid electrolyte materials, the sulfide-based inorganic solid electrolyte material having high ionic conductivity is obtained in a shorter time than the method for producing the sulfide-based inorganic solid electrolyte material in Examples. can understand

From the above, it can be understood that, according to the method for producing the sulfide-based inorganic solid electrolyte material of the present embodiment, the inorganic composition can be vitrified in a shorter time and the production time can be shortened.

This application claims priority on the basis of Japanese Patent Application No. 2019-066565 for which it applied on March 29, 2019, and takes in all the indications here.

Claims (8)

As a manufacturing method for manufacturing a sulfide-based inorganic solid electrolyte material containing Li, P and S as constituent elements,
A preparation step of preparing a raw material inorganic composition (A) containing at least lithium sulfide, phosphorus sulfide, and a crystal nucleating agent;
A vitrification process of vitrifying the raw inorganic composition (A) by mechanically treating the raw inorganic composition (A)
A method for producing a sulfide-based inorganic solid electrolyte material comprising a. In the method for producing the sulfide-based inorganic solid electrolyte material according to claim 1,
A method for producing a sulfide-based inorganic solid electrolyte material, wherein the crystal nucleating agent includes an inorganic solid electrolyte material. In the method for producing the sulfide-based inorganic solid electrolyte material according to claim 2,
A method for producing a sulfide-based inorganic solid electrolyte material, wherein the crystal nucleating agent includes a sulfide-based inorganic solid electrolyte material containing Li, P and S as constituent elements. In the method for producing the sulfide-based inorganic solid electrolyte material according to claim 3,
In the sulfide-based inorganic solid electrolyte material serving as the crystal nucleating agent, the molar ratio of the content of Li to the content of P (Li/P) is 1.0 or more and 10.0 or less, and the molar ratio of the content of S to the content of P (S A method for producing a sulfide-based inorganic solid electrolyte material having /P) of 1.0 or more and 10.0 or less. In the method for producing the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 4,
A method for producing a sulfide-based inorganic solid electrolyte material, wherein the content of the crystal nucleating agent contained in the raw inorganic composition (A) is 5% by mass or more and 60% by mass or less. In the method for producing the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 5,
The method for producing a sulfide-based inorganic solid electrolyte material, wherein the mechanical treatment in the vitrification step includes a mechanochemical treatment. In the method for producing a sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 6,
The method for producing a sulfide-based inorganic solid electrolyte material in which the mechanical treatment in the vitrification step is performed in a dry manner. In the method for producing the sulfide-based inorganic solid electrolyte material according to any one of claims 1 to 7,
A method for producing a sulfide-based inorganic solid electrolyte material, further comprising a crystallization step of crystallizing at least a part of the inorganic composition (B) by heating the obtained inorganic composition (B) after the vitrification step.